Why is my discount code SILVER21 not working on my site?

[ForageDesign]

Hello, 

I have created a discount code using the buy X get y format

Spend over £60, get a free pair of earrings with code SILVER21.  The code isn't working, an error message is coming up saying "SILVER21 discount code is not valid for the items in your cart"

I have selected all specific categories, and set no usage limits  .

my URL is www.foragedesign.com

here are some screenshots for you - the only screenshot i havent included is those of all the collections as tere are loads. i have selected all collections in my shop. 

[ForageDesign]

Update, - I have just tried creating a new code from scratch with the same rules "SILVER60" . same problem

[ForageDesign]

I got the fix in the end. 

If was because the item on offer wasn't manually added to the cart. S hopify doesnt add the free gift automatically.

Frustrating, as it effects the workability of the offer